Air conditioning system



NOV. 19, 1940. g P PP 2,222,237

AIR CONDITIONING SYSTEM Filed NOV. 8, 1933 2 Sheets-Sheet 2 FL- La. ms.

ITVENTOR.

.MMWP I Jimwgmm y Kha i ATTORNEY.

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atented Nov. 19, 1a

assassv V are oonorrroivmo srs'rerr Lawrence A... lihilipyr Detroit, Mich, assiynor. by

meme assignments, to Nash-Kelvinator Corporation, Detroit, Mich... a corporation of Maryland Application November d, 1933, Serial No. 697,1'ltl momma The present invention relates to the art of conditioning air and more particularly to the method of and apparatus for cooling and dehumidifying air.

One of the objects of the present invention is to provide an improved method of and apparatus for conditioning air, utilizing two heat absorbing sections in which a refrigerating medium is circulated first through one of the sections and then the other and varying the flow from one of the sections to theother in accordance with the condition of the air to be conditioned.

Another object of the invention is to control the flow of refrigerating medium from one of the heat absorbing sections to the other in accordance with variations of the relative humidity and/or the temperature of the air to be conditinned.

Other and further objects and advantages will be apparent from the following disclosure, reference being had to the accompanying drawings wherein preferred forms of embodiments of the present invention are clearly shown.

In the drawings:

Fig, 1 illustrates diagrammatically one form of the air conditioning system applied for cooling at room;

Fig. 2 is a longitudinal cross sectional view of an automatic throttle valve used in the system; and

Fig. 3 illustrates diagrammatically another embodiment of the invention.

My invention contemplates the use of a heat absorber of any suitable type having at least two heat absorbing surfaces. Both of these surfaces are utilized under normal. or low humidity conditions for removing principally sensible heat from the air and one of these surfaces is utilized also and particularly when the air to be conditioned is high in relative humidity, for cooling the air to below its dew point in order to cause precipitation and thereby remove a large part of the moisture from the air.

In the present embodiment an evaporator Ill of a mechanical refrigerator is employed as a heat absorber and the two heat absorbing surfaces of the heat absorber are provided by dividing the evaporator into two sections or portions ii and It. The flow of refrigerant by a feed pipe it to the evaporator Ill is controlled by an expan sion valve l5 and gaseous refrigerant is with drawn from the evaporator through a low pressure or suction pipe H.

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ceiver til. Gaseous refrigerant withdrawn from. the sections II and i2 passes through the suction pipe I I into the low pressure side of the compressor l8 wherein it is compressed and flows into the condenser It. It is liquefied in the condenser by being cooled and from the condenser the liquefied refrigerant flows into thereceiver 20 and then conducted through the expansion valve it to refrigerant feed pipe iii. The compressor is driven by a motor 22 which is controlled by a switch 23. It is to be understood that the capacity of the machine is such as to provide sufllcient refrigeration under abnormal high temperature and humidity conditions or both, of the air to be conditioned and that the refrigerating effect is varied in accordance with the conditions of the air to be conditioned.

The air conditioner herein illustrated is the type for cooling a room it such as an ofice or a living room in the home and the evaporator I0 is disposed in a cabinet as having an air inlet 25 and an air outlet 2i. The air is forced through the cabinet and about the evaporator it by a fan 2& driven by an electric motor to. A partition 3% extends downwardly from the top of the cabinet 25 and from the front to the rear for directing The sections it and M of the evaporator are arranged side by side and approximately onehalf of the air circulated passes about section II and the other half about section it. Section if: has approximately as much heat absorbing surface as section ll. order to increase the heat absorbing surfaces of sections It and I2, iins 3i and 32 are attached to these sections. Water collected on the evaporator drips to the floor of the cabinet 25 and is conducted out of the cabinet through a drain pipe 33. Preferably the heat dissipator is disposed outside of the room to be conditioned but in case it is desirable to have this machine in the me, the condenser and compressor are cooled by water so that the heat is carried out of the room in the water.

The primary or principal purpose of section I I is to remove sensible heat from all of the air passing thereover and although section, l2 will remove sensible heat from the air passing thereover, its function at times particularly when the relative humidity of the air to be conditioned is high, is to remove latent heat from the air by lowering the temperature of such air to below its dew point. It will be appreciated that the air in the room is subjected to different conditions due to changes in the temperature and humidity of the air outside the room and due to the direct addition of heat and moisture to the air within the room.

In order to maintain the air in the room between predetermined high and low temperature limits, a thermostat 34 is provided for controlling the operation of the heat dissipator. This thermostat is preferably disposed so as to respond to the mean temperature of the air in the room and controls the motor switch 23 by opening the same when the temperature of the air in the room attains a predetermined low value and closes the same when the temperature of the air attains a predetermined high value. Thus the temperature of the air in the room is maintained between certain limits by controlling the operation of the heat dissipator.

Not only is it desirable to control the temperature of the air in the room, but, it is also desirable to control the relative humidity of the air. When the relative humidity is high, the temperature of part of the air, as it passes through the cabinet 25, is decreased to below its dew point to cause precipitation of the moisture out of the air. The section l2 of the evaporator I is used for this purpose, it being designed and controlled to maintain at times a temperature much lower than that of the section II. Since the relative humidity varies independently of variations in temperature, it is necessary to remove varying proportions of moisture from the air while maintaining the temperature of the air between the predetermined fixed high and low temperature limits. In other words it is necessary at times to provide a low temperature to remove suflicient moisture and it is also necessary that the mean temperature of the air in the room should not be lowered below a predetermined limit. To provide these proper refrigerating conditions, I vary the amount of heat absorbed by different portions of the evaporator I0 by increasing and decreasing the temperature differential between these portions. These portions in the present disclosure are sections H and I2. When the relative humidity of the air to be conditioned 45 is relatively high, the section I2 is arranged to operate at a low temperature and the section II at a relatively high temperature. The tempera ture of the section 2 at this time will be low enough to cool a portion of the air to below its dew point and the amount of heat units removed by both sections is sufiicient only to maintain the temperature of the air in the room between its predetermined fixed high and low temperature limits.

The relative amount of heat units absorbed by sections H and I2 is controlled by a valve 35 which valve is controlled by a humidostat 36.

Valve 35 includes a main body 36*- forming a cylinder 31. The cylinder is provided with an inlet 38 which is connected with the outlet of section I and is provided with an outlet 39 which connects with the inlet of section I2. A pressure balanced piston 4| is disposed in the cylinder and is provided with two heads 42 and 43 which are connected with one another by a vnecl: 44. The bottoms 46 of metal cups 41 are sealed to the opposite ends of the piston 4| and the lips of the cups are sealed to ends of metal bellows 48. The opposite ends of the bellows 48 are sealed to the opposite ends of the main body 36 By this construction the ends of the cylinder 31 are sealed. The interiors of the bellows 48 are interconnected through the passage 50 in the piston 4| whereby the pressures within the bellows are equal. Cups and 52 are sealed with the opposite ends of body 36 and inclose the bellows 48. A sleeve 53 is sealed with the cup 5| and is provided with an outwardly extending end 55 which is internally threaded to receive a fitting 56 and is provided with an end 51 which extends within a cup 41. A coil spring 59 is disposed between the end of fitting 56 and the bottom of cup 41 and normally urges the piston 4| to the right. A bolt 60 is attached to the end of piston 4| and extends through the fitting 56. Nuts 61 are threaded on the end of bolt 60 which are ar ranged to engage the end of fitting 56 for limiting the right hand movement of piston 4|. A rubber end cover 62 is carried by the sleeve end 55 to prevent moisture ladened air from entering cup 41.

A volatile fluid containing bulb 64 is secured to the cup 52 and connected with the chamber 65 formed thereby so that the pressure on the exterior of bellows 48 is the same as the pressure in the bulb. An electrically operated heater 66 surrounds the bellows and is controlled by the humidostat 36. It will be observed, that when the pressure in chamber 65, acting on bellows 48, is sufiicient to overcome the resistance offered by spring 59, the piston 4| will be moved to the left.

The piston 4| is shown in its right hand position in which position only a restricted flow of refrigerant can flow about the right hand end of head 42. The size of this passage can be regulated by adjusting the nuts 61. When the heater 66 is energized, the pressure of the volatile fluid in bulb 64 and chamber 65 is increased sufliciently to move the piston 4| to the left to enlarge the passage at the right hand end of head 42 whereby an increased flow of refrigerant is permitted from section II to section |2.

The operation of the compressor I8 causes gaseous refrigerant to be withdrawn from the evaporator Ill. The liquid refrigerant under high pressure is delivered to the liquid receiver 20. A float 1|] within receiver 20 controls the expansion valve l5 by permitting the same to escape into feed pipe l3 at the rate liquid refrigerant is delivered to the receiver. Refrigerant will continue to flow through the evaporator l0 until the temperature of the air to be conditioned is reduced to a predetermined minimum at which time the thermostat 34 will operate the snap switch 23 to interrupt the motor circuit. The compressor l8 will remain inactive until the temperature of the air is raised toa predetermined maximum .tt which time the thermostat will close switch 23 to establish the motor circuit. The snap switch 23 includes a metal bellows 12 which is connected with the bulb 34 by a tube and this system contains a volatile fluid which causes expansion and contraction of bellows 12 in accordance with increase and decrease in temperature within room 24. The bellows 12 is arranged to move a movable contact 14 into and out of contact with a stationary contact 15 through a series of levers 11 and 18 and a spring 19. Contacts 14 and 15 are connected to the mains 80 and 8| which are controlled by a line switch 82. The humidostat 36 and the heater 56 are connected to the mains as follows: main 80, wire 84, humidostat 36, wire 85, heater 66, wire 86 and main 8|. The fan motor 29 is connected as follows: main 80, wires 84 and 88, motor 29, wires 89 and 86 and main 8|.

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aacaccv be increased which in eiTect provides a colder temperature in section it and a warmer temperature in section Ii. The air passing over section it will be cooled, by this relatively cold section to considerably below its dew point so as to cause precipitation and a consequent removal of more moisture from the air. Subject to the control of the refrigerating system by the thermostat t l, the system will continue to operate with the sections i l and it at materially different temperatures until the relative humidity of the room is lowered to the minimum humidity adjustment of humidostat lift at which time the heater to will be energized again to remove the restriction offered by valve llli and then the sections will again operate under equal pressures.

Thus it will be seen that I have provided an air conditioning system which maintains the air to be conditioned between predetermined limits by controlling the amount of refrigerating medium flowing therethrough and I have provided an air conditiorning system which removes moisture from the air, when desirable, by varying the te m perature differential between sections oi? a heat absorber by varying the flow of refrigerant medium from one oi the sections to the other. in this manner it is not necessary to reduce the temperature of all of the air circulating through the conditioner, which method would times necessitate the cooling of the air below its desired minimum, but by increasing the temperature of one oi the sections, at the time the other is lowered to a value suflicient to remove moi..- ture, the meantemperature or the air leaving the conditioner is no lower than when the sections are operating to; remove primarily only sensible heat from the air.

In the form or the invention shown in Fig. 3; the motor circuit is not only controlled. by the thermostat t l but also by the humidostat The circuit to the motor is controlled by two switches ti and till which are connected in par-- allel. fiwitch til includes a magnet coil tit, an armature contacts tit and hit. it spring ill tends to hold the contacts it and apart. When the coil is deenergised to complete a circuit to the motor as follows: main to, contacts and wire til, motor it and main ill. Elwitch it includes a magnet coil Mill, on armature till, contacts ltd and tilt. A. spring iitli holds the contacts tilt and tilt together when the coil iilll is deenergized and when the coil Mill is deener glued a circuit to the motor ilt is made as fol lows: main till, wire tilt, contacts tilt and tilt, wire till, motor ill and main ti, Thereiiore coil is energized or ii coil itil is deenerglsed, a circuit is completed to the motor.

The humidostat, in addition to controlling the heater coil controls the magnet coil The circuit for the heater db and coil illil includes main lit, wire t l, humldostat wire tilt, heater lit, wire ltd, coil Mill, wire l ill and main til. livhen the relative humidity at or below a predeter mined minhnum, the hdostat causes a circuit .and

to be completed through heater 6t and coil we whereby the now of refrigerant through valve 35 is unrestricted and the motor controlling con tacts itt and itt are separated. If however, the relative humidity is too high, the humidostat will operate to cause the circuit to heater coil to and contact lit to complete the motor circuit. Thus the refrigerating apparatus is controlled directly by the humidity of the air to be conditioned.

The thermostat lid, in addition to controlling the motor circuit, also controls the flow of refrigerant from section it or theevaporator to section. it. it valve i lit, similar to valve is interposed between valve and section it. it includes a heating coil lit which, when deenerglued, restricts the flow oi? refrigerant through the valve lit. in series with magnet coil and is controlled by thermostat o l through t he following circuit: main wire and lit, thermostat wire ilii, heating coil lit, wire ill, magnet coil wire 1! ill and main ill. air to be conditioned is at or below a predeter mined minimum, the thermostat is in a condition in which the circuit through coils lit and is interrupted whereby the flow of refrigerant through valve ll it is restricted and motor contacts till and lit are separated. It the tempo-rm ture of the air increases to above a certain degree, the thermostat closes the circuit through coils ii iiiand to remove the restriction of valve ill and causes the motor contacts and to I engage one another. The motor will then on erate the compressor it causing the temperature oi the evaporator to lower until the air in the room is decreased to a predetermined minimum.

The flow of refrigerant from section i i to section i tures until the relative humidity is lowered to the desired predetermined minimum although the thermostat has operated to break contacts lit thermostat has so operated, valve lit will further restrict the ilow of refrigerant from section it to section ill so to cause wider differential in temperature between these sections and a consequent greater precipitation or moisture with a slow decreasing of the mean temperature of the air leaving the cabinet.

When the relative humidity of the air is below, i

for eirample 50%, and the air reuuires cooling, the sections it and iii operate at the same term perature or substantially so. The valves and lit can be adjusted so that when the relative humidity oi the air is too high and the temperature or the air is too high, valve will maintain, :lor example, the suction temperature oi the refrigerant in evaporator 60 F. and that in section it at 38 and when the temperature oi the air is at its desired minimum and the relative humidity is still too high, the combined restrictions of valves and iii will maintain, for example, a suction temperature of the reirig The heating coll l is connected iii the temperature oi the will it at or Thus it will be understood that this system functions diiferently under three different conditions of the air. When the humidity is substantially proper, sections H and I2 operate at substantially the same temperature. When the humidity of the air is relatively high and when the air should also be cooled, valve 35 will cause the section H to be increased and the section [2 to be decreased in temperature. And when the 'air is reduced to the desired low temperature but the humidity is still too high for comfort, the valve H2 causes a further increase in differential between sections I l and i2 to cause a removal of a relatively large amount of moisture from the air.

Under certain conditions, it will be desirable to cause some precipitation of moisture at the sections II and I2 when the valves 35 and H2 are open, and it is to be understood that when said section or portion II is referred to asfunctioning to remove principally sensible heat, such terms are used merely to define the main functional purpose of the section as distinguished from the main functional purpose of section or portion I2 at the time valves are closed.

While the forms of embodiments of the present invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

I claim:

1. The process of cooling and dehumidifying air which comprises causing the air which is to be conditioned to circulate in heat exchange relation with a portion of an evaporator of a mechanical refrigerator, and in heat exchange relation with another portion of the evaporator, causing refrigerating medium to fiow first through the first mentioned portion of the evaporator and then through the second mentioned portion, controlling the heat exchange between the air and the evaporator in accordance with the temperature and relative humidity of the air to be conditioned, and while the refrigerating medium flows through the evaporator, varying the flow of refrigerating medium from the first to the second mentioned portions of the evaporator in accordance with the change in the relative humidity and temperature of the air to be conditioned.

2. An air conditioning system comprising in combination, a refrigerating system including an evaporator, said evaporator including a first portion and a second portion connected with the first portion for receiving refrigerant therefrom, and means intermediate said portions for controlling the fiow of refrigerantfromthe first to said second mentioned portions of the evaporator in response to changes in the relative humidity of the air to be conditioned.

3. An air conditioning system comprising in combination, a refrigerating system including an evaporator, said evaporator including a first portion and a second portion connected with the first portion for receiving refrigerant therefrom, means for controlling the heat exchange between the air and the evaporator in response to the temperature of the air to be conditioned, and means intermediate said portions for controlling the flow of refrigerant from the first to said second mentioned portions of the evaporator in response to changes in the relative humidity of the air to be conditioned.

4. The process of cooling and dehumidifying air which comprises causing the air which is to be conditioned to circulate in heat exchange relation with a portion of an evaporator of a mechanical refrigerator, and in heat exchange relation with another portion of the evaporator, causing refrigerating medium to flow first through the first mentioned portion of the evaporator and then through the second mentioned portion, controlling the heat exchange between the air and the evaporator in accordance with the temperature of the air to be conditioned, and while the refrigerating medium flows through the evaporator, controlling the fiow of refrigerating medium from the first mentioned portion to the second mentioned portion in accordance with changes in relative humidity and temperature of the air to be conditioned.

5. The process of cooling and dehumidifying air which comprises causing the air which is to be conditioned to circulate in heat exchange relation with a portion of an evaporator of a mechanical refrigerator, and in heat exchange relation with another portion of the evaporator, causing refrigerating medium to fiow first through the first mentioned portion of the evaporator and then through the second mentioned portion, controlling the heat exchange between the air and the evaporator in accordance with the temperature of the air to be conditioned, and while refrigerating medium flows through he evaporator, varying the fiow of refrigerating medium from the first mentioned portion of the evaporator to the second mentioned portion in accordance with the changes in the relative humidity of the air to be conditioned.

6. An air conditioning system comprising in.

changes in the relative humidity of the air to be conditioned.

7. An air conditioning system comprising in combination, a refrigerating system including an evaporator, said evaporator including a' portion, and including a second portion connected with the first portion for receiving refrigerant therefrom, means responsive to the relative humidity of the air to be conditioned for controlling the heat exchange between the air and the evaporator, and means intermediate said portions for controlling the flow of refrigerant from the first to said second mentioned portions of the evaporator in response to changes in the relative humidity of the air to be conditioned.

8. The process of cooling and dehumidifying air which comprises causing air, which is to be conditioned, to circulate in heat exchange relation with a portion of an evaporator of a mechanical refrigerator, and in heat exchange relation with another portion of the evaporator, causing refrigerating medium to flow from one of the portions to the other, and while refrigerating medium flows through the evaporator, varying the flow of refrigerating medium from said one portion to said other portion in accordance with the change in the relative humidity of the air to be conditioned.

The process of cooling and dehumidifying air which comprises causing air, which is to be 75 iii cnccnev conditioned, to circniate in heat enchance rein.- tion with o, portion oi an evaporator oi c, rne chanical refrigerator, and in heat exchange relation with another portion of the evaporator, reirigeratingmedium to iiovv iroin one oi the portions to the other, and While the reirigeroting medium is flowing through the even orator, varying the flow of reirigerating medium from said. one portion to said other portion in accordance with changes in the reiative i'rninid-= ity temperature of the air to be conditioned.

air conditioning system comprising, in combination, a refrigerating system including an evaporator, said evaporator including a first portion and a second portion connected with the :iirst portion for receiving refrigerant therefrom, and means intermediate said portions responeive to changes in the reintive humidity and the tern neratnre oi the on to ice conditioned for varying the new of refrigerant iroin the iiret to the second mentioned portion.

ii. rm air conditioning system comprising, in combination, a refrigerating system including an evaporator, said evaporator including a first portion and a second. portion connected with the first portion for receiving refrigerant therefrom, end moons responsive to the relative humidity and temperature of the air to he conditioned for controiiing the heat exchange between the air and the evaporator, and intermediate said portions responsive to the relative humidity and temperature of the air to ire conditioned for varying the flow of reirieernnt from the first to the second mentioned portion oi the evaporator.

MWENCE it. PIE 0 

